chassis tuning

Looking for advise with chassis. Have a home built jegs kit, strut front end, and four link rear. The car launches ok but was thinking my 60s should be quicker ( 1.40s)  Will try and include a video of a run. Curious if I should lower the rear of the car and reset my IC on my four link for better weight transfer.   429 (030) C6 5500 stall 5.00 gear 14x32.https://youtu.be/LZxq94HB8cY

Looks to me like it dead-hooked, and then needed more at-launch torque to keep the sidewall wadded up longer. Which caused it to snap unwind the sidewall giving it a little hop-skip. Either add more power, or adjust for more wheel-speed/less dead-hook at the initial hit.

What does the 4-link map look like the way the car sits now? Depending on how the housing brackets/chassis brackets are currently mounted (in relation to each other) changing the ride height a given amount might drastically limit your usable IC options. You won't know for sure until you map the 4-link.

How does it scale?

635 lf 709 rf 733 lr and 544 rr. driver in car and fuel. spread on four bars is 10.5 to 6.5. The ic point i can measure is 9.5 above the track surface and 2 inch below the neutral line 50 inches from rear axle center line. I have not tune the carb or set timing above 32 degree yet, spend time working out launch on car. Big question, leave it alone or lower. I do have a 514 and 532 that i am assembling now however was hoping to get chassis good before installing one, both are aluminum rod engine and do not want to test suspension with those. https://youtu.be/BA1pzymCY9A

Where do you have the shocks set? In slo-mo the wheel seems to be moving up and down quite a bit more than it should.

qa1 double adj compression 2 clicks from softest rebound 10 clicks from softest . Qa1 springs 95 pound. I have 120 springs that I have not tried yet.

Something i learned from an old guy at the track was to push down on the back of the car real hard to simulate the launch. Then count how many seconds it takes to decompress the shocks. You want a smooth and somewhat slow rise. It looks like in the video your rebound is too loose. It’s bouncing up instead of holding down. I’d have to check my book to be sure but I think your settings are the same as mine and it works good. But mine is ladder bars.

Meh, put the desired engine in the car and tune the chassis for that engine combo. Chassis tuning with the smaller/lower power engine first most times won't get you dead-nuts for the bigger power engine anyway. Usually what happens is as you add more and more at-launch power the car tries to launch more and more to the left....sometimes drastically hard to the left. This is especially true with a 4-link/anti roll.

As for the shocks I have always found it better to "count clicks" starting from full-tight and clicking back (not full loose and clicking forward). But regardless of where you start counting IMO having the compression/bump setting 2 clicks from full-soft is waaaay too loose. As a starting point just ballpark the rear shocks with the extension/rebound set a little tighter than half their total adjustment range, and the compression/bump set a little less than half their total adjustment range, then work from there.

If the 95lb springs are holding the car up-off the coilover shock snubbers, AND they also have the shocks sitting at the recommended C/C measurement, AND they also have the car sitting at the desired ride height, then the 95lb spring is probably in the ballpark. IMO a 120lb rear spring sounds too heavy for a full chassis car that doesn't have monster power, or a power-adder to work with. I could see a 120/130lb rear spring on a heavier full chassis car (or a back-half car) in say the 3000+lb range. And even then it could depend on the front/rear weight bias.

I just looked at the new video shot from the driver side (IMO filming from Dr side is always preferred) and the sidewall wind-up looks better than the last video. But IMO the front suspension looks way too stiff. It looks like the car is bouncing on the front tire (like a basketball) instead of the front strut springs doing most of the work. If the Strange struts are old you might want to check them to see if they are seized-up (or maybe their valving is adjusted too tight). Or the strut springs spring rate might be too stiff for the car's weight (and/or weight bias).